From 8aab6adae2ef34812225dfb7bb7ef8741d70e043 Mon Sep 17 00:00:00 2001
From: soulgalore <peter@soulgalore.com>
Date: Wed, 6 Mar 2024 14:31:15 +0100
Subject: [PATCH] Report some Loaf data in upcoming Chrome

---
 browserscripts/pageinfo/loaf.js | 36 +++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)
 create mode 100644 browserscripts/pageinfo/loaf.js

diff --git a/browserscripts/pageinfo/loaf.js b/browserscripts/pageinfo/loaf.js
new file mode 100644
index 000000000..d1d085be5
--- /dev/null
+++ b/browserscripts/pageinfo/loaf.js
@@ -0,0 +1,36 @@
+(function() {
+    // See https://developer.chrome.com/docs/web-platform/long-animation-frames
+    if (PerformanceObserver.supportedEntryTypes.includes('long-animation-frame')) {
+    
+    const MAX_LOAFS_TO_CONSIDER = 10;
+    const relevantLoadEntries = [];
+    const observer = new PerformanceObserver(list => {
+        let longestBlockingLoAFs = [].concat(list.getEntries()).sort(
+          (a, b) => b.blockingDuration - a.blockingDuration
+        ).slice(0, MAX_LOAFS_TO_CONSIDER);
+
+        // re-package
+        for (let entry of longestBlockingLoAFs) {
+            const info = {};
+                info.blockingDuration = entry.blockingDuration;
+                info.duration = entry.duration;
+                info.styleAndLayoutStart = entry.styleAndLayoutStart;
+                info.renderStart = entry.renderStart;
+                info.scripts = [];
+                for (let script of entry.scripts) {
+                    const s = {};
+                    s.forcedStyleAndLayoutDuration = script.forcedStyleAndLayoutDuration;
+                    s.invoker = script.invoker;
+                    s.invokerType = script.invokerType;
+                    s.sourceFunctionName = script.sourceFunctionName;
+                    s.sourceURL = script.sourceURL;
+                    info.scripts.push(s);
+                }
+                relevantLoadEntries.push(info);
+          }
+        return relevantLoadEntries;
+      });
+      observer.observe({ type: 'long-animation-frame', buffered: true });
+    }
+})();
+  
\ No newline at end of file